Low-fat food

A low-fat grilled cheese sandwich. Researchers said Tuesday that a low-fat diet seemed to slow the metabolism more than a low-carb diet. "Insulin is the bad guy," says Dr. Robert Lustig.

A low-fat grilled cheese sandwich. Researchers said Tuesday that a low-fat diet seemed to slow the metabolism more than a low-carb diet. "Insulin is the bad guy," says Dr. Robert Lustig. (Richard Chamberlin/Los Angeles Times)

A low-fat grilled cheese sandwich. Researchers said Tuesday that a low-fat diet seemed to slow the metabolism more than a low-carb diet. "Insulin is the bad guy," says Dr. Robert Lustig.